Tractor



Dec. 4, 1928. v 1,694,226

A. McDowALL TRACTOR Filed Dec. 31, 1923 5 sheets-sheet 1 Dec. 4; 1928. 1,694,226

f A. MGDOWALL 4 TRACTOR 5 Sheets-Sheet 2 `Filed Dec. 3l,

IMM Hnamcwfffvowa Dem, 1928` 1,694,226 A. -McDowALL TRACTOR Filed Dec. 31, 1923 5 sheets-sheet 3 Dec. 4, 1928. I 1,694,226

A. MnowALL TRACTOR Filed Dec. 31, 192s s sheets-sheet 5 Iwan/507.1'- no'ewjc ozacd Patented Dec. 4, 19.28.

yUNITED STATEiS ANDREW MCDOWALL, F CASTLE ])O`ll\"rfIntkSj SCOTLAND.

TRACTOR.

Application led December 31, 1923, Serial No.

This invention has reference to tractorsl and has for its object the construction of a tractor suitable for agricultural purposes adapted to be driven by an electric motor carried thereby and supplied by electrical energy from a stationary source.

My invention therefore has first for its object to provide a tractor of simple con,- struction adapted to be operated electrically and suitableA for the purpose above set forth.

A further object is to provide improvements whereby wear and tear of the insulating of the cable supplying current to the tractor is reduced to a minimum.

A further object is to provide improved steering arrangement for such tractor.

A further object of my invention is to provide an auxiliary apparat-us for use in combi.- nation with such tractor and by which the electric current can be supplied to the latter.

My invention has further for its object to provide further improvement which will be hereinafter set forth.

On the annexed sheet of drawings,

Figure 1 is a front elevation.

Figure 2 a plan view and Figure 3 is an end elevation of the im' proved tractor, the views illustrated beingl more or less diagrammatic part of the band being omitted in Figures 2 and 3 and part of the end of the chassis being omitted in F igure 3. l

Figure 4 illustrates diagranimatically a plan view of the tractor in combination with the auxiliary appliance above referred to.

F injure 5 is an elevation of said auxiliary apparatus a part of the tract-or chassis being also shown.

Figures 6 and 7 illustrate a side elevation and section respectively of a portion of th band.

Fig. 8 is a sectional line 8 8, Fig. 2.

Referring to the drawings- T he chassis of the tractor comprises a longitudinal framework l of angle iron and to which is secured the substantially triangular framework 2.

Journalled in bearings carried by the chassis are the two axles 3, 3ad on which are mounted the broad wheels 4, 4, and the sprocket wheels 5, 5. An endless band `6 passes over said wheels and also over the idle roller 7 which is journalled in bearings 8`secured to the framework. A

Carried by the chassis is the motor 9 which elevation taken on the 653,807, and in Great Britain January 26, 1923 drives through change gear box 10 a shaft Y 10a, a worm 11 on said shaft and worm wheel 12, the shaft 13.

Loosely mounted on said shaft 13 are the two sprocket wheels 14, 14, and the pinion wheel 15, either of which can be clutched to the shaft by moving the dog clutch 16 into engagement therewith.

Driving chains 17 17, pass over said sprocket wheels 14 and also the sprocket wheels 5 on the axles. i

The shaft 10a has mounted thereon the variable pulley 19 over which passes a band 2()` to the variable pulley 21. Cn the shaft of the latter is the bevel wheel 22 which meshes with a bevel wheel 23 on the shaft 24. On the latter Vis the sprocket wheel 25 which, by means of a chain 26, drives the sprocket wheel 27 mounted on the shaft 28 on which is also mounted the side ground or steering,r wheel 29. A dog` clutch 19EL is provided to clutch the pulley 21 to its shaft. On an extension of the shaft 3a is a pulley 30 which drives by means of a band 32 a pulley 33 mounted loosely on a shaft 34 on which is the tractor trail cable drum 34?.

Pulley 33 has projections on one side which engagey withy a dog clutch 33L on shaft 34 as afterwards explained and thus drives shaft 34 and 'tractor drum 34a.

rlihe tractor' trail cable 34h, see Figures 4 and 5, is wound on said drum and is connected to slip rings 35 carried by the shaft 34 and from which the current is conducted to the motor while the other end thereof is connected to the slip rings 37 of the auxiliary apparatus which in turn is supplied by current from any suitable source by means of a cable 138 wound on. the drum 139 of said-l apparatus.

Pinion 15 meshes with the toothed wheel 38 secured to the spindle 39 on which is the worm 40 in mesh with the worin wheel 41 keyed to the longitudinal shaft 42 su pportcd by the brackets 43. Said shaft at its ends' is provided with crank arms 44 and the crank pins engage with bearings 45 carried by the vertical rods 46 which at their lower ends carry feet 47. Said rods slide in boxes 48 which are pivoted to the arms 49 and constitute the point about which said rods rock as will be hereafter explained. The arms 49 are pivoted to the chassis at 50, and swing over notched quadrants 50a as desired by attendant.

Before describing the construction and operation of the auxiliary apparatus I will first set forth the operation of the tractor when ploughing a furrow.

Current is supplied through the cable 138, slip rings 37, cable 34" and slip rings 35, to Which the end of the motor 9 is electrically connected, to the motor 9 which is thus set in operation.

Clutch 16 moved to engage with and drive the sprocket wheels 14 which in turn -through the chains 17, 17 drive the shafts 3 and 3fl and therefore the endless band (S. The tractor is therefore moved over the ground in a longitudinal direction. Simultaneously the side Wheel 29 is driven through the chain 26, bevel gearing 22, 23, belt 20 and variable pulleys 19 and 21. By varyingl the diameter ot' the pulley 21 the speed of rotation oi the side wheel 29 can be varied and by this means the tractor can be moved to the lett or right as may be desired and steering thereby etfected.

At the end of a furrow it is necessary to move the whole tractor bodily in a transverse or lateral direction. This is accomplished by operating clutch 19a so that the variable pul ley 19 is free on its shaft and operating clutch 16 so that sprocket wheels 14 are idle and pinion 15 driven. Said clutches may be interconnected to operate in unison by linkage of usual design.V The pinion 15 therefore drives the toothed wheel 38, worm 40, worm Wheel 41 and shaft 42. The cranks on the latter transmit their motion to theV rods 4G causing same to descend and liftthe tractor on its one side and by reason of the rods being pivoted at 48 moves the tractor to the side.

By lowering or raising the arms 46 over quadrants 50- the step or distance the tractor is moved transversely can be regulated to a greater or less extent as may be desired. Further by such adjustment the general fore and aft alignment ot tractor can also be lnade parallel to the last furrow ploughed.

A wheel 51 located at the other side of the chassis and carried by a rod 53b pivoted at 52, simultaneously brought into operation by means of the cable 53 connected at its one end to the said arm and to an eccentric, crank or the like 54 on the longitudinal shaft 42, thus lifting this side of tractor.

The wheel 51 then acts as a roller during transverse step of tractor after which it is again raised clear of the ground.

The helical spring 53a returns said roller to its normal position as shown in l'ull lines.

After having been so moved the clutches 19 and 16 are again operated to drive the side wheel 29 and band 6. Y

The arrangement wherebyv the drum 34a is rotated will be hereafter described.

The said auxiliary apparat-us and the manner in which it cto-operates with the tractor will now be described.

The apparatus comprises a three wheeled carriage 55, the drum 139 rotatably mounted thereon, a cable support 56, and a wheel 57, which may be a rubber treaded vehicle wheel, also rotatably mounted on the carriage on a vertical axis which also passes through the drum 139.

The front or steering wheel 58 of the carriage is mounted on an axle carried by the upright 59 to which is secured. a horizontallyI extending arm (5() which at its extremity7 carries rollers 61 and acts, as will be hereafter explained as a tiller arm to guide the carriage.

The triangular frame 2 of the cl assis has attached thereto the inclined surfaces 60a.

In operation the feeder cable 138 is laid across the centre of the field at right angles to the direction in which it is to be ploughed or otherwise cultivated, the one extremity of such cable being connected to the main power supply cable while the other end is Wound round the drum 139 and connectedto the slip rings 37.

The rollers (31 coact Vwith said cable.

The carriage is placed so that the upper end of the support 56 carried thereby in alignment with the drum 34a of the tractor and so that it will travel in the line ot the feeder cable. The tractor trail cable is connected to the slip rings 37 and passes up said support and from there to the drum 342.

Each time the tractor passes the apparatus one of said inclined surfaces 60 co-acts with the Wheel 57 thereby moving the carriage at right angles to the movement of the tractor. then the tractor passes the auxiliary appa ratus in one direction the wheel 57 is partly rotated thereby serving to wind the feed cable 38 on drum 39.

vWhen passing` in the other direction a pan'l and ratchet arrangeniient, not shown, prevents the drum 139 being rotated so as to unwind the feeder cable, and allows wheel 57 to act a roller on inclined surfaces 691 and thus thrust the auxiliary carriage in the required direction.

In like manner a whole field can be ploughed or otherwise cultivated, the earriage being automatiralty and intermittently moved so as to maintain the trail cable in substantial alignment with the drum ot the tractor and the lecder cable automatically wound up until the ield is ploughed.

During such movement Vthe cable 133 serves to maintain the arm (i9 in atignment therewith and thereby guides the carriage towards the main supply peint.

The extent to which the feeder cable drinn 139 is rotated each time the tractor passes the auxiliary apparatus and thereby co-acts with the wheel 57 depends on the amount of contact of the inclined surfaces 60il with the periphery of the wheel 57 and by adjusti the angle oi inclination of such surfaces relative to the line of movement of the tractor this amount of operating Contact .can be varied.

As the tractor traverses backwards and forwards it is necessary that thedrum 34a should be rotated to unwind `the cable 34h when the tractor is moving from the auxiliary apparat-us and rotated to Wind the kcable thereon when being moved towards same.

And it is further necessary that the drum 34l should be moved axially so as to maintain saine in proper alignment with the cable d4b after the transverse movement of the tractor and the movement vof the auxiliary apparat-us.

This is accomplished as follows 1V hen clntchlG is moved to drive the pinion l5 and shaft 42 a Wire cable 80, which is secured at its one end to a crank 81 on said shaft, pullsl a lever 82 pivoted to the frame 2 at 83 and to which lever the other end of the cable is secured. This lever at its other end is secured to a cross bar connecting the uprights 34C which support the drum 34a and therefore operates to move said uprights over the transverse angle iron rails 34d thus displacing the drum carried thereby so that it occupies the position shown in Figure 2 in which position the dog clutch 33 is driven by the pulley 33 and therefore drives the said drum.

During such movementof the uprights 34C the helical springs 84, which are secured to the uprights and to the frame, are put under ten- S1011.

A spring loaded bolt 84a co-acts with the uprights and serves to prevent same moving backwards under the tension of the springs.

The drum 34aL remains in such position until the tractor passes the auxiliary apparatus which latter co-acts with the push rod 3la and such rod, through lever 85, pushes inwards the rod 85a the inner end of which cai'- ries a wedge or like member 86, which in turn co-acts with and depresses the bolt 84a.

When the bolt is withdrawn the uprights 34, carrying the drum 34L is moved under the action of the springs 84 over the angle iron transverse rails 34d. This results in the drum 34a being moved to bring same into alignment with the trailing tractor cable. Further by such movement the dog clutch 33 is released from the pulley 33 thereby allowing the drum 34 to rotate and play out the fable 34h as required.

lhen the tractor again comes to the end of its longitudinal movement and it is again moved transversely the flexible cable 80 again operates to displace the drum 34a axially and also to bring the dog clutch 83EL into engagement with pulley 33 so that as the tractor moves towards the auxiliary apparatus the drum is rotated to wind on the cable-34h. In passing thc auxiliary apparatus the push rod is again opeiated to free the bolt and permit of the displacement of the drum.

In 'like manner the drum is displaced each time the tractor is moved transversely and each time the auxiliary apparatus is moved, the clutch 33a being simultaneously moved into and out of engagement.

By fixing t-he cable 80 to various points lof the lever 82 the axial movement imparted to the drum can be varied.

Such tractor only travels in a backward and forward direction and steering may be automatically effected by means of a member travelling in a furrow and operatively connected to the said variable pulley 19 in such manner as to automatically correct any tendency of the tractor to deviate from its course.

1n the arrangement shown the member comprises two discs 7 0 carried at the .extremity of an arm 71 whose upper and forked end is connected to the short upright rod 72 carried by the horizontally extending rod 72u. Said rod has rigidly secured thereto an arm 7 3 which in turn is connected by means of a telescopic arm 74 to the bell crank 75. The latter is connected to the longitudinally extending rod 7 6 which is connected to the pivoted roti 77 by which adjustment of the variable pulley 19 is eflected.

p By adjusting the rod 7 2a and telescopic arm 74 the discs 70 can be adjusted to move within furrows at various distances from the chassis.

Should the tractor deviate from its course the said discs 7 O, which travel ahead of the tractor in a previously made furrow, impart a partial rotary movement to the rod 72 which in turn through the aforesaid mechanism operates to contract or expand the variable pulley 19 and thereby cause the wheel 29 to travel. .faster or slower as the case may be. `i/lVhenever the tractor resumes its normal course the variable pulley is returned to its normal position. l

Such steering' mechanism is duplicated at both ends of the tractor, one of same being raised out of the furrow when travelling in one direction and lowered to its operative position when travelling in the other direction.

lt will be understood that hand control of the variable pulley and thereby the steering is also provided for.

To counteract any tendency of the tractor to tilt or rear when in operation a counterweight 63 is carried by an extension (S4 of the frame 1l, see Figure l, and is located at the end opposite to that at which the plough or the like is attached.

Said counterweight is transferred to the other end of the frame when the travel of the tractor is reversed.

When used for ploughing a suitable plough may be secured to each end of the tractor and the free ends of the ploughs connected by a chain or cable passing over drnms 66 so tl at when raising or loweringl a plough `the one counterbalances the other, or if both ploughs remain in contact with the ground the forward plough will be guided by the said cable, regardless of the Idirection in which the tractor may be traveling.

The ploughs or the like are preferably attachedrto the tractor by `means of a spring safety device 6T with a dash pot incorpoated, so that the pull is taken through the spring.

In operation said spring is at normal compression but if an obstruction is encountered the spring is further compressed thereby allowing the plough or the like to fall an increased distance behind the tractor. In doing so a cable or tbe like (37 operates to slow down the motor and finally bringing same to rest, or disengage a clutch in the transmission gear and thus stop the tractor.

Such `device is shown at the right hand end of the tractor, Figure 1, but when the discs 70 are down this becomes the front end of the tractor and the plough or the like is fitted to such discs at the other or back end thereof.

The band 6 as shown in Figures 6 and 7 and which may be of rubber, balata or gutta pereha and canvas or the like has secured at spaced distances apart by bolts or otherwise the cross bars 68, which are provided with grooves 69.

VVoun-d round the belt so as to lie within said grooves is a steel wire or cable 7 O. Cross bars 70l also provided with grooves are secured to the bars 68 so as to clamp the cable in position.

Projections 7l on the bars 70c serve to prevent the belt from slipping on the ground and the bent over ends 72 of the bars 68 serve to prevent the band slipping off the wheels.

It will be understood that where the ground is unsuitable for the employment of the band the wheels are provided with spurs or projections as in tractors at present in use.

IVhat I claim is 1. A tractor comprising a chassis, wheels supporting same, a motor carried by the chassis and arranged to drive said wheels,

a drum mounted on a horizontal axis and capable of axial displacement, means to move the tractor in a lateral direction, and means to displace said drum in an axial direction an d arranged to act in unison with the lateral displacement of the tractor.

2. A tractor comprising a movable chassis, a driving motor for said chassis, a ground or steering wheel located at the side of the chas sis or framework and driven from the motor, a vari able gear interposed between the ground or steering wheel and motor, and a member a dapted to travel in a furrow operatively connected to the variable gear to control automatically the steering of the tractor.

3. A tractor adapted to travel backward and forward in a substantially straightline comprising an electric motor, l. drum mounted on a horizontal axis and around which a cable can be wound and current supplied thereby from a convenient source to said motor, means actua-ted by said motor for moving the tractor in a lateral direction, means actuated by the tractor' lateral moving means for displacing said drum in an axial direction, means for rotating said drum to wind the cable thereon, and a clutch by which said drum can be released to rotate freely, to pay out said cable.

4. A tractor adapted to travel backward and forward in a substantially straight line comprising in combination an electric motor for driving the tractor', a drum for a cable per-- mitting current to be supplied to said motor, spring means for moving the drum axially in one direction, a catch to hold the drum against the action of said spring, means for moving the tractor bodily in a lateral direction, and means to simultaneously move the drum axially against the action of the spring.

5. A tractor adapted to travel backward and forward in a substantially straight line comprising an electric motor arranged to drive the tractor, a shaft extending longitudinally of the tractor, gearing to rotate said shaft and driven by said motor, means operated by the shaft to lift one side of the tractor and to traverse the tractor in a transverse or lateral direction, a wheel normally clear of the ground, means operated by said shaft to cause the said wheel to raise the other side of the tractor when the latter is being traversed.

6. A tractor comprising a chassis or framework, wheels supporting same, an endless band passing over said wheels, an electric motor carried by the chassis or framework and arranged to drive said band, a drum carried by said chassis or framework and around which a cable can be wound and current supplied from a convenient source to said motor, a ground or steering wheel located at the side of the chassis or framework, a variable drive interposed between said ground or steering wheel and the motor and by which the Vrotation of the former can be varied to steer the tractor, upright rods at the one side of the tractor, means for imparting a circumferential movement to the lower ends thereof to move the tractor laterally, and a wheel to support the other side of the tractor when so moved.

7. A tractor arranged to travel backwards and forwards comprising in combination a carriage, a wheel carried thereby and arranged to co-act with the tractor, a drum for a feeder cable operatively connected to said wheel, and a support for the cable to convey current to the tractor.

8. A tractor comprising a. carriage, a drum for a feeder cable carried thereby, a support for the tractor cable, slip rings to convey the current from the feeder cable to the tractor cable, and means arranged to co-act with the tractor to automatically and intermittently displace the carriage at right angles to the travel of the tractor and Wind the feeder cable on its drum.

9. For a motor driven tractor arranged to tra-vel backwards and forvv'ards an auxiliary apparatus comprising a carriage, a drum for a feeder cable, a support for a cable to convey current to the tractor, means arranged to co-act with the tractor and displace the carriage intermittently at right angles to tlie travel of tbe tractor and Wind ythe feeder cable on the drum, and means adapted to cooperate Witli said cable and automatically steer the carriage.

10. For a motor driven tractor arranged to travel backwards and forwards an auxiliary apparatus comprising' in combination a carriage, a Wheel carried thereby and arranged to co-act with the tractor, a drum for a feeder cable operatively connected to said Wheel, a support for the cable to convey current to the tractor, a steering arm for said carriage 'and means carried by said arm and adapted to co-act With said feeder cable.

ANDREW MCDOVALL. 

